Nanoparticles have many applications. They are used in medicine, in electronics, in cosmetics and sun creams, in deodorants, and as catalysts. New uses for nanoparticulate materials are an important area of research.
These uses depend on the high surface area to volume ratio of nanoparticles. Because so much of the material is on the surface, a small amount can do the same job as a larger amount of the same material in bulk. A catalyst, for example, works on its surface, so nanoparticles give a large surface for reactions to happen on.
Nanoparticles also have risks. Their effects on human health and on the environment are not fully understood, because they are so new and so small. Nanoparticles in sun creams or cosmetics could be absorbed by the body, or could be washed into rivers and soil. Because they may behave differently from the bulk material, it cannot be assumed that they are safe.
To evaluate a use of nanoparticles, you weigh the advantages against the disadvantages. Advantages include smaller quantities needed and new or improved properties. Disadvantages include possible harm to health or the environment and the uncertainty about long term effects. Use the information you are given in the question to decide which side is stronger for that purpose.